martin



(No Model.) 2 Sheets-Sheet 1f C. MARTIN. GUN BMBRASURE JOINT.

W Jeux' mz numoml. Lrmunmmma coMPANY.

(No Model.) 2 Sheets-Sheet 2. G. MARTIN.

GUN EMBRASURE JUINT.

No. 518,155. Patented Apr. 10, 1894.

FIGJIL www UNTTBD STATES PATENT Ormes.

CARL MARTIN, OF MAGDEBURG-BUOKAU, GERMANY, ASSIGNOR TO THE GRUSONWERK,OF SAME PLACE.

GUN-EMBRASURE JOINT.

SPECIFICATION forming part of Letters Patent No. 518,155, dated AprillO, 1894. Application filed February 3, 1891. SerialNo. 380,057. (Nomodel.)

To @ZZ whom, t may concern:

Be it known that I, CARL MARTIN, a subject of the King of Prussia,residing at Magdeburg- Buckau, in the Kingdom of Prussia, German Empire,have invented an Improved Gun- Embrasure Joint, of which the followingis a specification.

The invention hereinafter described relates to an improved joint fortightly closing the space between the gun and the embrasure inminimum-embrasure gun-carriages, which joint operates like astuffing-box and entirely prevents the entrance through the embrasureofthe powder-gases which leave the gun at a very high pressure.

It is well-known that, by the term, minimum-emlorasure,7 is understoodan embrasu re in an armor-plate or shield, in the center orapproximately in the center of which are situated the imaginary orvertical pivots or axes about which the gun is turned for verticalpointing or elevation and training, or, in an armorplated revolvingturret, for vertical pointing or elevation only. By this means, asindicated by the term minimum-embrasu re the smallest practicableembrasure is obtained, which bears somewhat tightly against.

the gun. Nevertheless these arrangements, even when the iong chase ofthe gun protrudes from vthe armor-plate, have the defeet that, on thefiring of the gun, the powder-gases issuing at a very high pressure fromthe muzzle, iind access through the embrasure-joint into the interior ofthe armor-plate shield and cause considerable inconvenience to thegunners. Numerous arrangements of embrasure-joints have been devisedwith the object of obviating this defect, but, up to the present time,none of these arrangements has fulfilled its purpose. The difficultylies in the fact that simple metallic joints permit the passage ofthepowdergases notwithstanding the greatest accuracy in the iitting of theparts, while hemp and asbestus joints, though they act Well at first,become useless after a few shots have been fired from the dun.

b Now the present invention has for its object to automatically form ahermetic joint 5o during the tiring, without interfering with themovableness of the gun.

In order that my invention may be fully understood I will proceed todescribe it with reference to the accompanying drawings, in which-Figure I is a vertical section of my improved gun embrasure joint. Fig.II is a horizontal section thereof. Fig. III is a vertical sectionshowing a modification. Y

Upon the gun A (Figs. I and II) is provided a collar B which is turnedto a convex form. The center of thecollar coincides with the point ofintersection of the virtual pivots for the vertical pointing orelevation and the training of the gun.v The embrasure is bored outcylindrically at the inner side to a certain depth to form a shoulder c2and also to form a kind of stuffing-box, in which a gland C having arecess c is fitted, this gland being secured and adjusted by means ofscrews D. The packing itself consists of a ring E turned or bored out inconcave convex form in'cross section and made of soft metal, forinstance, copper, which ring is litted accurately upon the collar B. Toenable the said ring to be placed upon the said collar, it is composedof two or more segments and to enable the collar to operate in themanner hereinafter set forth it is split or divided at z, (Fig. II) in aplane at right angles to its axis. The stufling-box gland C is turnedout conically at its forward end c and bears somewhat tightly againstthe ring E, which is turned to a corresponding form. If the nuts D weretightly screwed down, the ring E would, by means of the conical part ofthe gland C, be pressed so firmly against the convex surface of the ringB that the friction produced bet Ween these parts would not only renderthe pointing difficult, but would also cause much wear of thepacking-ring. The said screws D, however, are not intended to be tightlyscrewed down, but the parts are so adjusted that the pressure whichcauses the hermetic closing of the embrasure will take place only uponthe firing of the gun, and will be automatically effected by thepowder-gases, that is to say; the stufiing-box gland C is accuratelyfitted into the bore of the embrasnre (which may be provided at l with aleather packing) and is only tightened to such an extent that the ring Eacts IOO as a bearing but not as a packing. When, however, a shot istired, the powder-gases under a high pressure pass at 5 into the space@between the embrasure wall and the ring E, and force the front orconcave part of the said ring directly against the convex surface of thecollar B, and also force the ringE into the hollow cone of the gland C,thereby effecting a further tightening between E, B and C. The action ofthe arrangement represented in Figs. I and II, is in this respect thesame.

In the tiring, the tightness of the joint at 5 is somewhat diminished,but the powdergasespenetrating at this point cannot pass through theembrasure either at 2 or at 3 or 4:, and, therefore, they cannot enterthe interior of the armor-plate. After the firing, as soon as theexternal pressure is diminished, the copper ring E expands again, thatis to say, the pressure between the parts of the same and the collarB isrelaxed, and the gun can be easily pointed, without impairing thequality of the joint. This is the characteristic feature and at the sametime the chief advantage of the invention.

In the drawings, the embrasure-joint is adapted to a gun-carriage inwhich the gun is not moved backward by the recoil.

Fig. III shows a special arrangement for a revolving turret in which ahorizontal turning of the gun about a virtual pivot in the embrasure isnot necessary, as the training is eected by rotating the entire turret.In the construction of the embrasure-joint, no change is necessary whenthe training must be effected by turning the gun, as the spherical jointpermits motion in any desired direction. When the gun-carriage is soarranged that the gun will move backward in the recoil, the collar B isheld in any suitable manner in the embrasure, and is provided with astuffing-box or with a leather or other packing-ring which is tted uponthe long chase of the gun, the latter being turned cylindrical for thispurpose, so that the gun, during the recoil and running ont thereof, canslide in the collar B.

I claim- 1. The combination of an embrasure having a cylindrical bore atits inner side forming a shoulder, a collar surrounding the gun having aconvex surface, a ring of concaveconvex form in cross section fitting onthe collar against the shoulder, and the adjustable gland located in thebore, having a conical recess in its forward end occupied by the rearside of the ring; the shoulder, embrasu re, ring, and gland forming aspace between them into which the powder-gases enter from the front sideof the ring and force the latter against the collar and into the recessof the gland; substantially as described.

2. The combination of an embrasnre having a cylindrical bore at itsinner side forming a shoulder, a collar surrounding the gun having aconvex surface, a ring of concaveconvex form in cross-section, dividedcircumferentially and fitting on the collar against the shoulder, andthe adjustable gland l0- cated in the bore, having' a conical recess inits forward end occupied by the rear side of the ring; the shoulder,elnbrasure, ring and gland forming a space between them into which thepowder-gases enter from the front side of the ring and force the latteragainst the collar and into the recess of the gland; substantially asdescribed.

CARL MARTIN.

litnessesz HERMANN LUBOWSKI, EMIL KALLNECKER.

